The application relates to induction systems utilizing multiple valves for tuning an engine.
A typical modern induction system for a vehicle engine includes one or more valves used to regulate the flow through the induction system to tune the engine throughout its operating range to maximize engine performance. A typical induction system includes multiple primary runners that each supply air to one of the engine's cylinders. A plenum fluidly joins the primary runners upstream from the cylinders. The plenum receives air from a throttle body.
One example tuning configuration uses a plenum valve arranged within the plenum to regulate the flow between first and second chambers of the plenum that are respectively in fluid communication with first and second sets of primary runners. Opening or closing the plenum valve changes the effective tuning length from the throttle body to each cylinder. As a result, more than one torque peak can be provided by an engine.
The above described plenum valve has been used in combination with two additional valve configurations. The first configuration includes an individual valve provided within each primary runner. This configuration provides increased control of the torque over the engine's operating range. However, the resulting induction system is rather complicated and requires many valves, which is more difficult to package and greatly increases the cost.
The second configuration includes a spilt secondary runner arranged between the plenum and the throttle body. The split secondary runner includes a valve that is used to vary the effective diameter of the secondary runner to regulate the resonance of flow in the system. This configuration provides limited tuning at lower engine speeds.
What is needed is an induction system having minimum valves while providing effective engine tuning.